Certain medical procedures require the insertion of a viewing device, an “endoscope”, into a body cavity in order to view features and structures within the body cavity. Such an endoscope may be, for example, a gastroscope, pharyngoscope, laryngoscope, laparoscope, colonoscope or any other type of medical telescope. For the purpose of this disclosure, we shall use the term “endoscope” to include any viewing device that is inserted into the body of a subject and used to view internal structures. The endoscope may be rigid or flexible. Rigid endoscopes, such as standard laparoscopes, usually consist of a shaft of approximately 300-500 mm length, with an outer diameter of 5 mm to 12 mm, having an objective lens at one end and an eyepiece at the other end. In some instances, such as with fiber-optic gastroscopes, the device may be over a meter in length and may permit flexion and manipulation by the operator of the distal end. The shaft of the endoscope often contains light-transmitting fiber-optic bundles and/or lenses that transmit visual signals and light.
The endoscope also normally has a connection, adjacent to the eyepiece, for the attachment of an external light source which provides illumination, via light-transmitting fibers within the endoscope.
Prior to the introduction of a rigid endoscope, such as a laparoscope, the body cavity is generally inflated with a gas, usually carbon dioxide, using a gas insufflator.
Subsequently a plastic or metal sleeve or sheath, often referred to as a trocar, is inserted through the wall of the cavity. These sleeves contain a means of making a seal to prevent the leakage of gas from within the body cavity. The end of the endoscope containing the objective lens is inserted into the body cavity through the sleeve, the attached light-source activated and the features within the body cavity viewed through the eyepiece of the endoscope or on a video monitor receiving signals from a video camera attached to the eyepiece.
The objective lens of the endoscope often becomes soiled during operative procedure. Tissue particles, blood, mucous and other body fluids attach to the lens and obscure vision. The usual routine when such problem arises is to remove the endoscope from the patient's body and soak its distal end (the lens) in sterile water, wipe the lens with a sterile towel, and reinsert the laparoscope into the patient's body through the existing laparoscopic trocar. During some operative procedures, the endoscope may have to be removed frequently to have the lens wiped clean.
The loss of vision due to soiling of the objective lens of the endoscope can be a serious problem, especially if it occurs at a critical moment during surgery. It increases the time required for a procedure and necessitates repeated withdrawal and insertion of the endoscope which may produce trauma to the tissues. The covering of the objective lens of the endoscope by blood is often referred to as the “red video” sign. This is particularly serious if the bleeding is extensive and if time is wasted in removing, cleaning, and reinserting the lens. If clean, unobstructed lens is not available quickly enough for identification and control of the bleeding source, the procedure is more likely to be converted to an emergency “open” operative procedure requiring large surgical incisions.
A number of solutions have been developed for keeping the objective lens free of soiling. These include the use of water jets, ultrasound devices, liquid irrigation, and brushes (see U.S. Pat. Nos. 5,207,213, 5,549,543, 5,225,001, 5,167,220, 5,400,767, 5,514,084, 5,575,756, 5,830,127, 6,017,333, 6,354,992, 6,447,446, and patent publications US23109837A1, WO09220274A1, WO09532012A1). There are also several devices that solve the problem of fogging of the objective lens (see U.S. Pat. Nos. 5,549,543, 5,464,008, 6,712,479, and patent publication EP01153567A1). None of these describe or suggest the present invention.
There is clearly a long-felt need for devices and methods that maintain a clear and unobstructed view through the objective lens of an endoscope while in use; devices that clear obstructive fluids and debris from the optical/visual path of an endoscope while in use; and devices that eliminate the need for the endoscope to be withdrawn from the patient in order that the objective lens may be cleaned. There is a need for such devices that are simple and inexpensive to manufacture, that are simple to use and robust in use, and that can be used with a variety of endoscopic devices. The present invention provides such devices and methods of using them.